In general, regulated emissions for internal combustion (IC) engines include carbon monoxide (CO), hydrocarbons (HC), nitrogen oxides (NOx), and particulates. However, such regulations have become more stringent over recent years. For example, the regulated emissions of NOx and particulates from diesel-powered IC engines are low enough that, in many cases, the emissions levels cannot be met with improved combustion technologies alone. To that end, exhaust aftertreatment systems are increasingly utilized to reduce the levels of harmful exhaust emissions present in exhaust gas.
Conventional exhaust gas aftertreatment systems include any of several different components to reduce the levels of harmful exhaust emissions present in exhaust gas. For example, certain exhaust aftertreatment systems for diesel-powered IC engines include various components, such as a diesel oxidation catalyst (DOC), a selective catalytic reduction (SCR) catalyst, a diesel particulate filter (DPF), an SCR on filter, and/or an ammonia slip catalyst (ASC) (also referred to as an ammonia oxidation catalyst (AMOX)). Each of the DOC, SCR catalyst, DPF, SCR on filter, and/or the ASC components are configured to perform a particular exhaust emissions treatment operation on the exhaust gas passing through or over the respective components.